EXAFS and DFT Investigations of Uranyl Arsenate Complexes in Aqueous Solution.
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| Title: | EXAFS and DFT Investigations of Uranyl Arsenate Complexes in Aqueous Solution. |
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| Authors: | Gezahegne, Wondemagegnehu A.1 gezahegn@mailserver.tu-freiberg.de, Hennig, Christoph2, Tsushima, Satoru2, Planer-Friedrich, Britta3, Scheinost, Andreas C.2, Merkel, Broder J.1 |
| Source: | Environmental Science & Technology. 2/21/2012, Vol. 46 Issue 4, p2228-2233. 6p. |
| Subjects: | Environmental chemistry, Migration of uranium, Extended X-ray absorption fine structure, Density functionals, Uranyl compounds, Arsenates, Environmental chemistry experiments, Aqueous solutions |
| Abstract: | Uranium and arsenic often co-occur in nature, for example, in acid mine drainage waters. Interaction with arsenic is thus important to understand uranium mobility in aqueous solutions. For the present study, EXAFS spectroscopy was used to investigate the formation and identify the structure of aqueous uranyl arsenate species at pH 2. The nearest U-As distance of 3.39 Å, observed in shock-frozen liquid samples, was significantly shorter than that observed in solid uranyl arsenate minerals. The shorter bond length indicated that the solution contained a bidentate-coordinated species, in contrast to the monodentate coordination in solid uranyl arsenate minerals. The U-As coordination number of 1.6 implied that two uranyl arsenate species with U:As ratios of 1:1 and 1:2 formed in nearly equal proportions and that the hydrated uranyl ion was present only as a minor component. The two uranyl arsenate species could not be differentiated spectroscopically, since their U-As distances were equal. A comparison based on DFT modeling indicated for both the 1:1 and the 1:2 species, that the bidentate arsenates were bound to uranium with one of the binding oxygen atoms being protonated. Based on the present spectroscopic study, the two species that will have to be considered in acidic uranium-arsenic-rich solutions are thus UO2H2AsO4+, and UO2(H2AsO4)20. [ABSTRACT FROM AUTHOR] |
| Copyright of Environmental Science & Technology is the property of American Chemical Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 72446920 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: EXAFS and DFT Investigations of Uranyl Arsenate Complexes in Aqueous Solution. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Gezahegne%2C+Wondemagegnehu+A%2E%22">Gezahegne, Wondemagegnehu A.</searchLink><relatesTo>1</relatesTo><i> gezahegn@mailserver.tu-freiberg.de</i><br /><searchLink fieldCode="AR" term="%22Hennig%2C+Christoph%22">Hennig, Christoph</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Tsushima%2C+Satoru%22">Tsushima, Satoru</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Planer-Friedrich%2C+Britta%22">Planer-Friedrich, Britta</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Scheinost%2C+Andreas+C%2E%22">Scheinost, Andreas C.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Merkel%2C+Broder+J%2E%22">Merkel, Broder J.</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Environmental+Science+%26+Technology%22">Environmental Science & Technology</searchLink>. 2/21/2012, Vol. 46 Issue 4, p2228-2233. 6p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Environmental+chemistry%22">Environmental chemistry</searchLink><br /><searchLink fieldCode="DE" term="%22Migration+of+uranium%22">Migration of uranium</searchLink><br /><searchLink fieldCode="DE" term="%22Extended+X-ray+absorption+fine+structure%22">Extended X-ray absorption fine structure</searchLink><br /><searchLink fieldCode="DE" term="%22Density+functionals%22">Density functionals</searchLink><br /><searchLink fieldCode="DE" term="%22Uranyl+compounds%22">Uranyl compounds</searchLink><br /><searchLink fieldCode="DE" term="%22Arsenates%22">Arsenates</searchLink><br /><searchLink fieldCode="DE" term="%22Environmental+chemistry+experiments%22">Environmental chemistry experiments</searchLink><br /><searchLink fieldCode="DE" term="%22Aqueous+solutions%22">Aqueous solutions</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Uranium and arsenic often co-occur in nature, for example, in acid mine drainage waters. Interaction with arsenic is thus important to understand uranium mobility in aqueous solutions. For the present study, EXAFS spectroscopy was used to investigate the formation and identify the structure of aqueous uranyl arsenate species at pH 2. The nearest U-As distance of 3.39 Å, observed in shock-frozen liquid samples, was significantly shorter than that observed in solid uranyl arsenate minerals. The shorter bond length indicated that the solution contained a bidentate-coordinated species, in contrast to the monodentate coordination in solid uranyl arsenate minerals. The U-As coordination number of 1.6 implied that two uranyl arsenate species with U:As ratios of 1:1 and 1:2 formed in nearly equal proportions and that the hydrated uranyl ion was present only as a minor component. The two uranyl arsenate species could not be differentiated spectroscopically, since their U-As distances were equal. A comparison based on DFT modeling indicated for both the 1:1 and the 1:2 species, that the bidentate arsenates were bound to uranium with one of the binding oxygen atoms being protonated. Based on the present spectroscopic study, the two species that will have to be considered in acidic uranium-arsenic-rich solutions are thus UO2H2AsO4+, and UO2(H2AsO4)20. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Environmental Science & Technology is the property of American Chemical Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1021/es203284s Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 6 StartPage: 2228 Subjects: – SubjectFull: Environmental chemistry Type: general – SubjectFull: Migration of uranium Type: general – SubjectFull: Extended X-ray absorption fine structure Type: general – SubjectFull: Density functionals Type: general – SubjectFull: Uranyl compounds Type: general – SubjectFull: Arsenates Type: general – SubjectFull: Environmental chemistry experiments Type: general – SubjectFull: Aqueous solutions Type: general Titles: – TitleFull: EXAFS and DFT Investigations of Uranyl Arsenate Complexes in Aqueous Solution. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Gezahegne, Wondemagegnehu A. – PersonEntity: Name: NameFull: Hennig, Christoph – PersonEntity: Name: NameFull: Tsushima, Satoru – PersonEntity: Name: NameFull: Planer-Friedrich, Britta – PersonEntity: Name: NameFull: Scheinost, Andreas C. – PersonEntity: Name: NameFull: Merkel, Broder J. IsPartOfRelationships: – BibEntity: Dates: – D: 21 M: 02 Text: 2/21/2012 Type: published Y: 2012 Identifiers: – Type: issn-print Value: 0013936X Numbering: – Type: volume Value: 46 – Type: issue Value: 4 Titles: – TitleFull: Environmental Science & Technology Type: main |
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